Bioenergy – Butanol, Miscanthus

Displacing America’s dependence on petroleum is the goal behind Hans Blaschek’s research on butanol. He has been studying microorganisms that are used in fermentation processes for over 25 years. About 10 years ago, his lab at Illinois had a breakthrough with the development of a mutant strain of a soil bacterium called Clostridium beijerinckii that produces higher concentrations of butanol when added to a vat of plant byproduct. Because the mutant strain produces higher concentrations of butanol, it is the basis for Tetravitae BioSciences, a company that licensed the patented strain from the University of Illinois and is scaling up to use the over-productive strain on a large scale -- the size of an ethanol plant.

On the University of Illinois South Farms is the 320-acre Energy Farm, which is devoted to growing crops that could be used to produce renewable energy. The land is planted with Miscanthus, switchgrass, corn, and restored prairie as potential bioenergy crops. The goal is to compare insect and disease challenges, environmental benefits, economic opportunities, and potential energy per acre of each.

In the largest field trial of its kind in the United States, Steve Long and his team of researchers determined that the giant perennial grass Miscanthus substantially outperforms current biofuel sources. He believes that using Miscanthus as a feedstock for ethanol production would significantly reduce the amount of farmland needed for biofuels. Using corn or switchgrass to produce enough ethanol to offset 20 percent of gasoline use would take 25 percent of current U.S. cropland out of food production. Getting the same amount of ethanol from Miscanthus would require only 9.3 percent of current agricultural acreage. Because Miscanthus is a perennial grass, it also accumulates much more carbon in the soil than an annual crop such as corn or soybeans. In the context of global change, that is important because it means that by producing a biofuel on that land, you are taking carbon out of the atmosphere and putting it into the soil.

Not everyone is convinced by the Miscanthus research results, however. U of I researcher Gregory McIsaac analyzed water quantity and quality in plots of Miscanthus, switchgrass, corn, and soybeans and found that Miscanthus used substantially more water but reduced the potential for nitrogen pollution to water bodies.

Despite the advantages of using Miscanthus for bioenergy, work by Madhu Khanna and her team of researchers shows that significant policy incentives are needed to induce farmers to convert land from existing uses to Miscanthus production. However, the use of high yielding non-food based feedstocks such as Miscanthus can mitigate the food vs. fuel competition for land and the negative impact of biofuel production on food prices.